Almost every where in Yogya, Solo, Semarang and other cities in Central Java, in Karatons, in the market, in the villages, in the hotel's lobby, you should hear the magical melodious percussion music - the gamelan Javanese orchestra.

In his book 'music of Java' Jaap Kunst says, "Gamelan is comparable to only two things, moonlight and flowing water. ...mysterious like moonlight and always changing like flowing water ...".

Gamelan music is an integral part of all cultural activities in Java such as wayang kulit (leather puppets) performance, court dance, uyon-uyon (symphony orchestra performance), etc. There are two kinds of laras (tuning) in gamelan, namely slendro (comparable to minor key in Western music) and Pelog (major key). A complete set of gamelan consist of two sets of different instruments of Slendro and Pelog, such as:

Kendang (double ended drum beaten by hands)
It is a leading instrument. The pengendang (drumer) is the conductor of the gamelan orchestra. There are five (5) different sizes of kendang from 20 cm to 45 cm.

Saron
A glockenspiel with bronze bar struck with wooden mallet. There are three kinds; Saron Barung, Saron Peking, Saron Demung.

Bonang Barung
A double row of bronze kettles resting on a horizontal frame, played with two long stick bound with red cord at the striking end.

Bonang Penerus

Slentem
Thin bronze bars suspended over bamboo resonating chambers, struck with a padded disc on the end of a stick.

Gender
Similar to slentem with more bronze keys and smaller bamboo chamber, struck with two disc-shaped hammers.

Gambang
Wooden bars laid over a wooden frame struck with two sticks of supple buffalo horn, ending with a small, round, padded disc.

Gong
Each slendro and pelog set had three gongs. Two big gongs (Gong Ageng) and one gong Suwukan about 90 cm, made from bronze, suspended on a wooden frame. It marks the end of the largest phrase of the melody.

Kempul
Smaller gongs, marks a smaller phrase. In each slendro and pelog set, there are 6 (six) or 10 (ten) kempuls.

Kenong
Smaller gongs lay horizontally on crossed cord, inside a wooden frame. A complete set of kenong in each slendro and pelog consist of 10 (ten) kenongs.

Ketug
The kenong player also plays it smaller kenong, marks subdivisions of phrases.

Clempung
A string instrument, each slendro and pelog set needs one clempung.

Siter
Smaller cemplung, each slendro and pelog set needs one siter

Suling
It is a flute, each slendro and pelog set, needs one suling.

Rebab
A two stringed viol, the same as slendro and pelog.

Keprak and Kepyak
Needed for gamelan to accompany dances.

Bedug
It is a very big drum.

The bars of the gamelan instruments can be made either from iron, copper or bronze. The bronze bars are the best choice. All the gamelan players are sitting cross-legged on a mat during a performance.

In a gamelan music concert or karawitan performance, the Kendang player or pengendang conducts the Tempo, while the melody is led by the bonang player

The gamelan orchestra includes some singers (Pesinden), female as well as male. There are some very famous Pesindens, their names are almost known by everybody in this region.

Some believe that in the ancient time, the first set of gamelan, by the name of Lokananta was created by gods and played in Mount Lawu, Eastward of Solo.

In short the history of gamelan was as follow:
The first gamelan was the three-toned Munggang, then the five-toned slendro gamelan and the last: the seven-toned pelog gamelan.

Patet
In the laras slendro, there are:

Slendro patet nem

Slendro patet sanga

Slendro patet manyura

In the laras pelog, there are:

Pelog patet lima

Pelog patet nem

Pelog patet barong

Patet is a place to lay the gending or to establish the gending. In the wayang kulit (shadow puppet) whole night show, the gamelan plays,
Slendro patet nem from 9.00-12.00 p.m.
Slendro patet sanga from 00.00-03.00 a.m.
Slendro patet manyura from 03.00-06.00 a.m.

For an experienced gamelan player it should not difficult to determine the patet of a particular gamelan music. Or it can be said that patet is used to create mood, with the gamelan accompaniment. It is already known that various gamelan tunes are played to create different atmosphere of the situation or feeling such as joy, sorrow, anger etc.